Do not use too popular hashtags or else your content will dissolve in flood of other FB pages content. Use unique or pretty rare hashtags. But use A LOT of them. If you`ll use them often enough you`ll get some traffic from FB search in several months.
"I do promoted posts every day. Am I supposed to just add them at the end like on Twitter? How do multi-word hashtags work? Do you need commas?" You don`t need commas.) #pink_widgets Try to use hashtags inside your text and limit them with 2 (or 4 if the text is large. Try to make them less annoing for users.
I plea ignorance of the whole concept: where exactly would people see posts marked with hashtags? Only in "search for people, places and things"? Does anyone still search for people given that everyone's got hundreds of FB acquaintances already and new people are suggested to you every day. And, since it's Facebook, why would you search for things (or anything other than people for that matter)?
One thing I would love to know about those hashtags is this: what makes a post with a hashtag appear on the actual FB page for that hashtag. Not every post that contains a hashtag #example appears on the [facebook.com...] page, that much I know. Also, the posts that do appear, sometimes show up 20+ minutes after they were posted, and then they are gone from that page after some random time on it, not necessarily only after being pushed down by newer posts.
So, this all looks like a very unpredictable system. Does anyone have an idea about how FB picks posts to show for that hashtag?